Here\'s what Histogen will be forced to do -- hear me now, believe me later

First of all, in this post I AM NOT implying that Histogen will be approved and become available soon in the US. There is a slim chance it might happen within 2 years or so, but most likely it will be on the far side of that.

However, when it does happen, this is what I think they will be FORCED by the FDA to do… and mark my words.

We already know that all the protocols they’ve been testing, all the reports, summaries, descriptions, studies, etc. about Histogen’s “Hair Stimulating Complex”, HSC, entail the following: THE SCALP INJECTIONS ARE LIMITED TO ABOUT 2-3 SESSIONS PER YEAR, NO MORE.

Never once, anywhere to my knowledge, have they ever tested or publicized a study or clinical trial where they administer these HSC injections more than about twice a year (i.e., once every 6 months).

If anyone can show me evidence that they’ve tested it for more frequent treatments, please speak now.

This means that they already KNOW that no regulatory agency will approve anything more frequent. This is a done deal.

Why? Because HSC contains growth factors that are known to be involved with serious potential side effects, like cancer, when too much of these growth factors are absorbed from exogenous sources into the body.

For example, VEGF, which is in HSC, is thought to promote the growth of cancerous tumors, when absorbed in too-high quantities. Therefore the FDA will be VERY CAREFUL about what they eventually approve, when reviewing Histogen’s application.

I realize these growth factors are already present in the body and are just lab-synthesized versions of what already is produced in the body.

The issue is not where they come from, the issue is QUANTITY. How much can safely be put into the body from an outside source, with the approval of the government? The FDA will deem there are reasonable limits to this.

I know that some people are wildly bandying about scenarios where they’ll be able to get HSC injections, say, once a month or every week.

I’d have to say that’s bunk… the wildest and most unrealistic type of pie-in-the-sky dreaming.

Face reality.

So, here’s what I can predict Histogen will be FORCED BY THE FDA to do in the USA:

  1. HSC will be administered by physicians only. Only doctors will be authorized to prescribe it and administer it. It will be impossible for you to legally buy HSC and inject it into your own scalp, unless you somehow manage to get it on the black market.

  2. ALL doctors who want to treat their patients with HSC will have to register to obtain it. Their registration information will go into a big database, and Histogen, along with the FDA, will monitor this database in real time.

  3. Any patient who wants to get HSC treatment will be able to get it from only one physician or clinic at a time.

  4. It will be unlawful for a patient to have more than, say, 2-3 injection sessions of HSC per year.

  5. Any patient who tries to circumvent this rule by obtaining more frequent injections, say, by visiting multiple doctors in multiple cities, will be immediately caught when his name shows up multiple times in the database. He will be instantly prohibited from obtaining more HSC injections than the prescribed (for example) 2-3 treatments per year.

  6. Furthermore the FDA will make their approval of HSC conditional on Histogen agreeing to all of the above.

I don’t see why oncogene transformation would be a risk with the amounts that Histogen is using. Even if it were to be done on a monthly basis.

It’s much more likely they use a new vehicle a la follicept… where they can use less but still deliver it effectively.

I’m not saying they use follicept’s tehcnology… there are at least 4-5 other similar vehicles being developed (all based on university IP). One example is at harvard. Of course one example is follicepts.

I’ll look for the links.

The point is, histogen started when these new vehicles didn’t exist, so they will probably only now start to think about using them…

[quote][postedby]Originally Posted by roger_that[/postedby]

  1. ALL doctors who want to treat their patients with HSC will have to register to obtain it. Their registration information will go into a big database, and Histogen, along with the FDA, will monitor this database in real time.

[/quote]

I might be wrong but I have never heard that FDA has ever spent the time and money to set up, maintain, monitor and track the usage of a particular medication and I don’t think they will start doing that because of a hair loss treatment.

I didn’t say the FDA would fund or maintain the database – only that they would mandate it and have access to it. The costs would be absorbed by Histogen, and to some extent, by the prescribing doctors (and ultimately by the patients). And of course, if Histogen or the docs were found to be putting false information in the database, they’d be held liable.

Apart from that, the FDA often does just what I’m talking about. See the page below, under the heading “REMS Modifications”, the second bullet point under “Examples of minor changes include” –

You might be shocked at how deeply the FDA gets involved in monitoring and overseeing the use of certain approved drugs, behind the scenes.

[quote][postedby]Originally Posted by needhairasap[/postedby]
It’s much more likely they use a new vehicle a la follicept… where they can use less but still deliver it effectively.

I’m not saying they use follicept’s tehcnology… there are at least 4-5 other similar vehicles being developed (all based on university IP). One example is at harvard. Of course one example is follicepts.

I’ll look for the links.

The point is, histogen started when these new vehicles didn’t exist, so they will probably only now start to think about using them…[/quote]

Why would they? Injections are extremely effective already. Past the stratum corneum diffused distribution is possible. The rest is mostly depended on the pharmacokinetics of the delivered compound(s).

If you are going to use less the pharmalogical response will be weaker. Depended on the pharmacokinetics of the delivered compounds a advanced vehicle might be beneficial though for instance in having a “continuous” delivery.

In that sense a advanced vehicle which has the same effectiveness as injections might be better because of better efficiency. For instance instead of the need of constant injections daily it could be delivered through some sort of advanced vehicle.

However then a question arises which is a interesting one; Will it work better with more frequent applications? Perhaps not at all…

Anyway interested in those links. Would be cool if you can find them.

I think the FDA will either approve it or turn a blind eye. There are plenty of medications and consumer products on the market that may potentially cause cancer, I just can’t imagine the FDA getting involved by asking the manufacturer to set up a database.

This is a good read, FDA doesn’t always act in the best interest of the consumers,

"Dr. Gloria Troendle, deputy director for the Division of Metabolism and Endocrine Drug Products for the FDA, noted that the cholesterol-lowering drug gemfibrozil belonged to a class of drugs that has repeatedly been shown to increase death rates among users. Moreover, Dr. Troendle stated that she does not believe the FDA has ever approved a drug for long-term use that was as cancer causing at human doses as gemfibrozil.

Others shared these same concerns about gemfibrozil. In comments to the FDA, Elizabeth Barbehenn, Ph.D., concluded: “fibrates must be considered as potential human carcinogens and their carcinogenic potential should be part of the risk benefit equation for evaluating gemfibrozil.”

Ignoring these facts and despite having a majority vote among their advisory committee against approval, the pharmaceutically- campaigned FDA-approved these drugs anyway! Specifically, when asked to vote whether or not the cholesterol-lowering drug gemfibrozil should be approved for prevention of heart disease, only 3 out of 9 voted in favor of approval. Unfortunately, these votes are only “advisory” and – against the better judgment of the committee – the FDA decided to approve gemfibrozil for human consumption."

[quote][postedby]Originally Posted by LIG[/postedby]
I think the FDA will either approve it or turn a blind eye. There are plenty of medications and consumer products on the market that may potentially cause cancer, I just can’t imagine the FDA getting involved by asking the manufacturer to set up a database.

This is a good read, FDA doesn’t always act in the best interest of the consumers,

Others shared these same concerns about gemfibrozil. In comments to the FDA, Elizabeth Barbehenn, Ph.D., concluded: “fibrates must be considered as potential human carcinogens and their carcinogenic potential should be part of the risk benefit equation for evaluating gemfibrozil.”[/quote]

You raise some good points, but the magazine you cite, The People’s Chemist, is involved in advocacy. So of course they’re out to present the best “evidence” and anecdotes that would support their arguments and their agenda. That doesn’t mean that the FDA always acts in that way, or that’s indicative of any kind of norm for the FDA.

However, let’s compare gemfibrozil with Histogen’s HSC. One is a drug to lower cholesterol. It’s highly doubtful that patients will be rushing to “abuse” this drug and take more and more of it, because everyone is so excited about lowering their cholesterol. Much more likely, patients will be satisfied with whatever dosages their doctor prescribes, and will have no incentive to want more, or to go doctor shopping so they can get multiple prescriptions for gemfibrozil from multiple doctors.

By contrast, with HSC, there will be a HUGE incentive for patients to want to use more and more of the stuff, pushing the boundaries of the suggested dosage and treatment protocol.

And I think this is a bit different from, say, Rogaine. With Rogaine, there is an established recommended dosage, approved by the FDA, published by Upjohn and prescribed by doctors. And yet, there are no controls on patients who want to use more and more of the stuff, because you can just buy it (over the counter now) and use as much as you want. If you want to rub Rogaine into your scalp for 10 straight hours a day, no one is going to stop you – the only thing stopping you is that, if enough is absorbed into your circulation, your blood pressure might plummet and you go into hypotensive shock.

But with Histogen’s HSC, we know the company is conducting trials of this stuff specifically using a protocol which calls for injected dosages spaced out at around 6 month intervals – twice a year. The highest dosage I’ve heard contemplated (I think) was maybe 3 treatments per year or something like that.

That is coming from the company itself. Moreover, it is highly unusual for any drug manufacturer, ever, to contemplate a regimen for any drug with such widely-spaced dosages.

That tells me that Histogen is being very, very cautious. They want their product to be approved. But they feel they have to be so cautious as to do what is almost never done for any drug – except, perhaps, in the case of some chemotherapeutic agents and the like – contemplating a treatment protocol of only twice a year???

Doesn’t that fact, in and of itself, tell you something?

[quote][postedby]Originally Posted by needhairasap[/postedby]
It’s much more likely they use a new vehicle a la follicept… where they can use less but still deliver it effectively.

I’m not saying they use follicept’s tehcnology… there are at least 4-5 other similar vehicles being developed (all based on university IP). One example is at harvard. Of course one example is follicepts.

I’ll look for the links.

The point is, histogen started when these new vehicles didn’t exist, so they will probably only now start to think about using them…

[postedby]Originally Posted by Swooping[/postedby]

Why would they? Injections are extremely effective already. Past the stratum corneum diffused distribution is possible. The rest is mostly depended on the pharmacokinetics of the delivered compound(s).

If you are going to use less the pharmalogical response will be weaker. Depended on the pharmacokinetics of the delivered compounds a advanced vehicle might be beneficial though for instance in having a “continuous” delivery.

In that sense a advanced vehicle which has the same effectiveness as injections might be better because of better efficiency. For instance instead of the need of constant injections daily it could be delivered through some sort of advanced vehicle.

However then a question arises which is a interesting one; Will it work better with more frequent applications? Perhaps not at all…

Anyway interested in those links. Would be cool if you can find them.[/quote]

Swoop, I dont have enough knowledge to have a discussion, but I still don’t understand how a (“new-age”) topical vehicle would be less efficient than injections… this is just my common sense guess… of course I know reality is often counter-intuitive (i.e. common sense doens’t pan out).

I just don’t see, for instance, how injecting HSC into the center of the scalp (presumably into the bloodstream) would be more efficicent at getting where it needs to go (ie. even distributed amongst the scalps follicles), than would a topical being applied evenly across the scalp.

Of course, the above is under the assumption that (1) the topical can deliver the molecule through the skin, (2) the goal is to get the molecule around all of the follicles in the scalp and (3) the topical application and injections use the same amount of “solution/HSC”

I just don’t see how the “follicles treated per unit of solution” would be higher for a injection than a “new-age” topical vehicle. Injection comes across, to me, like shooting bird-shot out of a shotgun… hopefully some gets through the bloodstream to the follicles.

It seems like it’s

topical > straight to follicles

vs.

injections > through bloodstream > (hopefully some gets) to follicles

anyway, histogen has been dicking around for a decade. I think it is much more likely they just go out of business and disappear.

We’re talking about the people who claimed these shots would be available in asia in 2013… we’re now half way through 2015 and having it available in asia with in the next 5 years is probably questionable.

I’ve pretty much given up on replicel/histogen…

Replicel doesn’t even know what they do. First they were a histogen-like injections. Now their pitch sounds more like multiplication/cloning lauster style.

The issue is these companies talk about what they want to do (in other words what the ideal situation would be: “oh, we hope that it’s one injection a year and the hair keeps growing”; “oh, we hope that it will be a small tissue sample, then you’ll come back in a week and we’ll implant 10,000 multiplied follicles”.)

ask either company what they can actually do today, or even in the next 365 days and they will both say:

uhhhhhhhhhhhhhh… we may be able to grow another 100 hairs on your head-- we think… we’ll need to raise money first though, and then the process of planning a trial takes about 1 year… whats that you say? how can project management take an entire year? Oh, well, we’ll have to get back to you on that. That’s just how “these things” go.

[quote][postedby]Originally Posted by LIG[/postedby]
I think the FDA will either approve it or turn a blind eye. There are plenty of medications and consumer products on the market that may potentially cause cancer, I just can’t imagine the FDA getting involved by asking the manufacturer to set up a database. [/quote]

Exactly. It doesn’t make sense for the FDA to care much about Histogen dosage wise too if we look at it rationally.

The hair stimulating complex of Histogen secretes the proteins in a nanogram range. The VEGF concentration for example is only 121ng/ml. That is pretty damn low.

Now let’s look at a cosmetic product which is on the market already. Something like Dermaheal HL; Amazon.com. Has IGF-1, bFGF & VEGF in the formulation. The only difference being is that these are derived from e.coli. Look at the dosage in this formulation though; 10ppm. That is 10µg/ml!

So the concentration of this specific product has almost 100x more VEGF in it than the hair stimulating complex of Histogen.

It’s true that inducing growth factors at high dosages continuously can lead to a higher risk of carcinogenesis. But that would need to be on way another level;

Regranex is human recombinant PDGF-AA; Server Error. Guess what the concentration is? 0.01% = 100PPM = 100ug/ml!! That is like at least 500-1000X the concentration that Histogen has. It is true that this product has shown to have a increased mortality risk from cancer when people used 3 tubes or more (black-box warning). But that equals to 45 gram use at that concentration on a open wound (ulcer)! That is insane, and on a way way way higher concentration & frequency than Histogen.

One could go on with something like Mecasermin…

So yeah… Realistically I highly doubt the FDA would care about the concentration that Histogen is using even if it were to be more frequent applications. Some OTC products already have way stronger concentrations than Histogen has… Go figure :p…

Then again Histogen isn’t that effective anyway seeing from their phase 2 data. I would call it a total fail honestly. It’s never going to hit the market in my opinion. Replicel same story, even worse from what we have seen till now.

Agree 100%, it has never been FDA’s job to monitor and track consumption of approved medications in order to assess dosage abuse and they are not going to start with Histogen because they fear that HSC may cause cancer.

Swooping, I agree with everything you’ve said there regarding concentrations, but maybe concentration alone isn’t the issue, but rather chronic exposure. So that, chronic exposure to VEGF, even at the low concentrations we’re talking about, would be considered a cancer risk.

My understanding of the VEGF cancer link is that (as you alluded to earlier) it is not an initiator or promotor of oncogenes, but rather promotes angioneogenesis and neo-vascularization which helps tumore grow.

So let’s say – just hypothetically – a patient has a microscopic lesion of precancerous or cancerous cells in his lung. Chronic exposure to higher-than-normal levels of VEGF in the blood (as a result of many successive HSC treatments) could plausibly put the person at greater risk that this tiny lesion may grow bigger and metastasize, being fed by more and more vessels that resulted from the exogenous supply of VEGF. Whereas a “control” subject with a similar microscopic lesion, who didn’t receive the exogenous VEGF, might be safer and the lesion might be successfully nipped in the bud early by immune system and macrophages, or at least grow much slower and be less acutely aggressive.

Same could be said for any kind of lesion in the body (I’m not an oncologist so maybe the pulmonary example isn’t the best one)… colon, liver, kidney, brain, testicles, etc.

It isn’t hard to envision that, given the way VEGF works and given its empirically demonstrated link to tumor promotion, that chronic exposure to excessive VEGF above normal body baseline levels might be considered a risk.

By the way, I am NOT suggesting in this thread that HSC will be a great treatment and will grow a lot of hair, as long as we can use a lot of it, like every week or something. That’s something certain people like Jarjarbinx are always harping on, and that’s not my belief.

I was just trying to illustrate one reason why it’s not realistic to put our hopes in ANY kind of topical, injectable, or any other type of proposed hair loss cure, other than a strictly live cell-based one.

I still have to ask the question, though, to all of you bright people here.

That question is this: One would think Histogen would want to present its product in the best possible light, and demonstrate the maximum possible results from HSC. Why, then, would they limit testing to a protocol of twice a year? Why would they not, at least once, test it with a protocol of 12 monthly treatments, or even bimonthly or weekly injections?

We have some very smart people here, and some obviously scientifically well-educated people like you. But also it seems we have some people who want to duck issues and avoid questions. I am just trying to get someone to answer the above question clearly and succinctly, with a scientifically defensible answer.

[quote][postedby]Originally Posted by LIG[/postedby]
I think the FDA will either approve it or turn a blind eye. There are plenty of medications and consumer products on the market that may potentially cause cancer, I just can’t imagine the FDA getting involved by asking the manufacturer to set up a database.

[postedby]Originally Posted by Swooping[/postedby]

Exactly. It doesn’t make sense for the FDA to care much about Histogen dosage wise too if we look at it rationally.

The hair stimulating complex of Histogen secretes the proteins in a nanogram range. The VEGF concentration for example is only 121ng/ml. That is pretty damn low.

Now let’s look at a cosmetic product which is on the market already. Something like Dermaheal HL; Amazon.com. Has IGF-1, bFGF & VEGF in the formulation. The only difference being is that these are derived from e.coli. Look at the dosage in this formulation though; 10ppm. That is 10µg/ml!

So the concentration of this specific product has almost 100x more VEGF in it than the hair stimulating complex of Histogen.

It’s true that inducing growth factors at high dosages continuously can lead to a higher risk of carcinogenesis. But that would need to be on way another level;

Regranex is human recombinant PDGF-AA; Server Error. Guess what the concentration is? 0.01% = 100PPM = 100ug/ml!! That is like at least 500-1000X the concentration that Histogen has. It is true that this product has shown to have a increased mortality risk from cancer when people used 3 tubes or more (black-box warning). But that equals to 45 gram use at that concentration on a open wound (ulcer)! That is insane, and on a way way way higher concentration & frequency than Histogen.

One could go on with something like Mecasermin…

So yeah… Realistically I highly doubt the FDA would care about the concentration that Histogen is using even if it were to be more frequent applications. Some OTC products already have way stronger concentrations than Histogen has… Go figure :p…

Then again Histogen isn’t that effective anyway seeing from their phase 2 data. I would call it a total fail honestly. It’s never going to hit the market in my opinion. Replicel same story, even worse from what we have seen till now.[/quote]

  • 1 (except for the part about Histogen being a total fail. I think that the problem with Histogen is that follicles are not being exposed to it often enough. I think it needs to be gotten to the follicles more frequently, especially in the beginning…the first 4 - 6 months.)

[quote][postedby]Originally Posted by needhairasap[/postedby]
anyway, histogen has been dicking around for a decade. I think it is much more likely they just go out of business and disappear.[/quote]

Yes, actually I think you’re right. I think this is the most likely scenario.

My point in starting this thread was just to give one more reason why all this dicking around with topicals, injectibles, growth factor suspensions/solutions, chemicals, pills, drugs, wounding and plucking ideas will not ultimately lead to the cure.

As I stated in my “We’re deluding ourselves” post, the only real MPB cure will come from a live cell-based procedure. End of story.

[quote][postedby]Originally Posted by needhairasap[/postedby]
anyway, histogen has been dicking around for a decade. I think it is much more likely they just go out of business and disappear.

[postedby]Originally Posted by roger_that[/postedby]

Yes, actually I think you’re right. I think this is the most likely scenario.

My point in starting this thread was just to give one more reason why all this dicking around with topicals, injectibles, growth factor suspensions/solutions, chemicals, pills, drugs, wounding and plucking ideas will not ultimately lead to the cure.

As I stated in my “We’re deluding ourselves” post, the only real MPB cure will come from a live cell-based procedure. End of story.[/quote]

Roger, keep in mind that injectibles, pills, and topicals have already regrown some hair. And since they have regrown SOME hair why is it unreasonable to believe that better topicals might possibly produce even better regrowth. It’s not like there has been zero regrowth with injectibles, topicals, and pills.

Actually, to this point in time, injectibles, topicals, and pills have regrown more hair than cell-based treatments. It’s my recollection that Replical and Aderans increase hair volume by about 7%. Topicals, pills, and injections have increased volume by as much as 15%. This means that topicals, injections, and pills are twice as effective as cell-based treatments thus far. And I think it’s too early to say we’ve reached the upper limit of regrowth with topicals, injections, and pills.

For one thing, they are creating better and better topical delivery vehicles. Right now, in order to get enough medicine into the body to have a dramatic effect on hair growth you would have to apply so much of the medicine that it would absorb systemically and cause undesirable side effects. But once they have vehicles that can deliver a medicine to an exact spot in the skin w/o getting into the body that could produce a breakthrough tropical treatment for hair loss. Last I heard there are potentially 3 or 4 such vehicles in the pipeline.

For a second thing, it may be possible to get better results by getting more growth factors to the follicles via more repeat injections. I really don’t think that the FDA is going to present impenetrable blockades to this because the dose of these injections is relatively low. Just like Swooping said, there are already products in the marketplace that contain substantially higher doses of these growth-factors than the hair growth-factor treatments contain.

Yes I agree that chronic exposure could be different roger_that, even at a low concentrations. Or that it could act as a catalyst indeed to pre-cancerous cells.

Was just showing some examples of other products that are on the market in comparison with the concentration of histogen. You can see some of that here in figure 1C btw;

http://www.researchgate.net/profile/Robert_Kellar/publication/51769149_Hair_regrowth_following_a_Wnt-_and_follistatin_containing_treatment_safety_and_efficacy_in_a_first-in-man_phase_1_clinical_trial/links/0c960533eae61a36a9000000.pdf.

Anyway you raise a good question why they wouldn’t test a protocol of more frequent injections. My guess is that it wouldn’t really be viable from a selling point perhaps? They did injections at baseline and at 6 weeks in the phase 2 trials. So that is 6 weeks apart. Let’s assume that the cost of such a treatment would be $2000. Not everyone could be shelving out that money for a year long right? I’m terrible at such things perhaps someone else got a answer to this.

However the question arises like you mention if increasing frequency will yield better results? Bear with me now.

All of the “growth factor treatments” whether that is

-SGF57 http://www.imediway.com/)
http://static.wixstatic.com/media/9f3cb6_5a5bdada6158435ead83a698bba69083.jpg_srz_p_918_849_75_22_0.50_1.20_0.00_jpg_srz

-AAPE
http://www.eplasty.com/images/PDF/eplasty15e10.pdf

or Histogen
http://www.histogen.com/downloads/iid_2013_hsc_final.pdf

They all show on average 10-15% increase in total hair count. Now if we look into a recent paper called “ Resting no more: re-defining telogen, the maintenance stage of the hair growth cycle” (2014) they state as many may know that in a adult human scalp the average percentage of telogen hair follicles is around 10-15%. This means that even Brad Pitt with his thick norwood 1 has around 10-15% of hair follicles in telogen.

More importantly what they say in the paper and had my interest is the following ;

Well I think you all get where I am heading. Perhaps these growth factors just prompt telogen hair follicles into anagen. Isn’t it ironic that a scalp has 10-15% hair in telogen and all these so called “growth factor” based treatments all give around 10-15% growth? Is that what we need though? Off course not! We need to prompt these stupid AGA miniaturized hair follicles into a healthy growing state not the healthy telogen hair follicles! The art is into reversing these “unhealthy” hair follicles not in prompting anagen in healthy hair follicles lol.

To support this even more nothing came close yet to being a hair growth stimulating compound like minoxidil right? Obviously minoxidil isn’t a growth factor itself. But doesn’t it have impact on these growth factors too?

So wouldn’t it be plausible that minoxidil already has some sort impact on these growth factors just in a different way? Minoxidil is applied 2x daily generally and has a half life of 8 hours. Talk about frequency here!

That’s why I think acting on these growth factors is not the solution. I might be wrong though. I hope so! One thing is for sure, it proves damn hard to treat AGA. Minoxidil is sitting for almost 35 years at the top now. That says enough I guess.

I know it’s just anecdotal but I did get virtually 100% reversal of hair loss with RU. The only reason I quit is that I got systemic side effects.

[quote][postedby]Originally Posted by jarjarbinx[/postedby]
I know it’s just anecdotal but I did get virtually 100% reversal of hair loss with RU. The only reason I quit is that I got systemic side effects.[/quote]

what side effects? gyno?

“Well I think you all get where I am heading. Perhaps these growth factors just prompt telogen hair follicles into anagen. Isn’t it ironic that a scalp has 10-15% hair in telogen and all these so called “growth factor” based treatments all give around 10-15% growth? Is that what we need though? Off course not!”

Boom. I think you’re right, Swooping. I’ve never heard this take before, but this is an excellent analysis.

Jarjar, are you paying attention to this? I think Swooping has identified something very important here, i.e. why growth factors and other “stimuli” never seem to revive more than 10-15% of follicles.

Also Swooping, I think you’re dead on about Minoxidil. Minoxidil is an antihypertensive that works in several related ways – by dilating small blood vessels, and by upregulating VEGF which results in more microscopic blood vessels being made. This is not surprising, because it’s not uncommon for related processes in the body to be mediated by similar (or the same) biochemical pathways. Dilating existing microvasculature, and creating new micro-vessels, would both tend to lower peripheral blood pressure, so it’s no coincidence that one chemical can induce both effects simultaneously.

HSC is not just reliant on VEGF, but other growth factors as well – but all these growth factors would seem to be susceptible to that 10-15% ceiling in what they can potentially accomplish.